If you have Kickstarter County 2, then its simple! Open the route menu, select Kickstarter County 2, select the Multiplayer session.
Once the game has loaded, you will find a screen with the rules of the game. You can choose how many people you want driving, how many drivers one guest can claim, and if the session is private or not. Once you hit "start," the session becomes available to anyone who has TRS2019 in general. Hope you found this helpful!